=== Zookeeper Configuration Store

The Zookeeper Configuration Store extends the Vert.x Configuration Retriever and provides the
way to retrieve configuration from a Zookeeper server.

It uses Apache Curator as client.

==== Using the Zookeeper Configuration Store

To use the Redis Configuration Store, add the following dependency to the
_dependencies_ section of your build descriptor:

* Maven (in your `pom.xml`):

[source,xml,subs="+attributes"]
----
<dependency>
  <groupId>io.vertx</groupId>
  <artifactId>vertx-config-zookeeper</artifactId>
  <version>3.4.1</version>
</dependency>
<dependency>
  <groupId>io.vertx</groupId>
  <artifactId>vertx-config</artifactId>
  <version>3.4.1</version>
</dependency>
----

* Gradle (in your `build.gradle` file):

[source,groovy,subs="+attributes"]
----
compile 'io.vertx:vertx-config:3.4.1'
compile 'io.vertx:vertx-config-zookeeper:3.4.1'
----

==== Configuring the store

Once added to your classpath or dependencies, you need to configure the
`link:../../yardoc/VertxConfig/ConfigRetriever.html[ConfigRetriever]` to use this store:

[source, ruby]
----
require 'vertx-config/config_retriever'
store = {
  'type' => "zookeeper",
  'config' => {
    'connection' => "localhost:2181",
    'path' => "/path/to/my/conf"
  }
}

retriever = VertxConfig::ConfigRetriever.create(vertx, {
  'stores' => [
    store
  ]
})

----

The store configuration is used to configure the Apache Curator client and the _path_ of the Zookeeper node
containing the configuration. Notice that the format of the configuration can be JSON, or any supported format.

The configuration requires the `configuration` attribute indicating the connection _string_ of the Zookeeper
server, and the `path` attribute indicating the path of the node containing the configuration.

In addition you can configure:

* `maxRetries`: the number of connection attempt, 3 by default
* `baseSleepTimeBetweenRetries`: the amount of milliseconds to wait between retries (exponential backoff strategy).
1000 ms by default.